1. Field of the Invention
The present invention relates to an MPEG-4 Part 14 (MP4) demultiplexer and a method of operating the same, and more particularly, to an MP4 demultiplexer and a method of operating the same, enabling an MP4 file to be played in a fast-play mode inputted by a user.
2. Description of the Related Art
Recently, as a multimedia container format standard for multiplexing and compressing multimedia contents (such as digital video, audio, subtitles and still images), MP4 has been receiving much attention. MP4 is being widely used as a container file format for digital video files encoded by the MPEG-4 standard and digital still images encoded by the next-generation JPEG 2000 standard.
MP4 is based on Apple's Quicktime container format and is used internationally as the file format for the Third Generation Partnership Project (3GPP/3GPP2) and as the standard file format for VOD files by telecommunication service providers in Korea. As such, MP4 is being widely used in wireless telecommunication networks.
In mobile communication devices, multimedia content is now stored and transmitted in the MP4 file format. Correspondingly, multimedia content provided by content service providers and telecommunication service providers are also in the MP4 file format.
Accordingly, mobile communication devices such as mobile phones are provided with functions for playing multimedia content in MP4 file format in which one of these functions enables users to play the multimedia content at a desired position during a play mode.
However, since the mobile communication devices in general have limited processing capabilities, multimedia content in MP4 file format cannot be decoded fast enough to play the multimedia content in a fast-play mode.
Specifically, most mobile communication devices can only decode 15 frames per second for an image having a size of 176×144 pixels, in contrast to a conventional personal computer which has enough processing capability to decode “avi” and “asf” files to enable a fast play of 2× to 4×. Therefore, in view of the processing capability and power consumption of the mobile communication devices, it is difficult to realize in the mobile communication devices the fast decoding conventionally provided by personal computers.
Further, when the mobile communication devices are used for various purposes such as language studies which often require multimedia content to be played in replay and fast-play modes, such functions cannot be provided due to the slow decoding capabilities of the mobile communication devices.